基于有限元法和疲劳理论的电缆水树老化机理

Study of the Water-Tree Aging Mechanism Based on the Finite Element Method and Fatigue Fracture Theory

针对电缆水树老化问题,本文通过水针电极老化法加速XLPE绝缘水树老化,研究水树的微观形态,并建立了基于电场仿真和材料疲劳断裂理论为基础的水树老化模型。研究结果表明:Maxwell应力作用下的XLPE分子链会发生疲劳,疲劳累积导致分子链断裂形成微孔和裂纹,随着疲劳断裂的发展及水分的积累,逐渐发展形成相互连接的充水微孔和细枝,并最终发展形成水树。

This paper focuses on XLPE cables water-tree aging problem, a water-needle electrode method was used to accelerate water tree aging, the micro morphology is studied; Based on the electric field simulation and fatigue fracture, a water tree model is established to analyze and discuss the mechanism of the water tree aging. The studies show- that fatigue fracture of the XLPE molecular chains, caused by the Maxwell stress, resulting in plenty of water-filled micropores and cracks are formed.With the development of fatigue fracture and the accumulation of water,water-filled branches and viods gradually formed and eventually interconnected together to form the water tree.